Eclipse - "Run" button causes errors and doesn't run

Hello there, i've been trying to make a mod and well it isn't going as planned and i need your help please.

When i hit the "Run" button it gives me this :

[00:17:54] [main/INFO]: No arguments specified, assuming client.

[00:17:54] [main/INFO]: Extra: []

[00:17:54] [main/INFO]: Running with arguments: [--userProperties, {}, --username, ForgeDevName, --tweakClass, cpw.mods.fml.common.launcher.FMLTweaker, --accessToken, {REDACTED}, --assetIndex, 1.7.10, --assetsDir, C:/Users/********/.gradle/caches/minecraft/assets, --version, 1.7.10]

[00:17:54] [main/INFO]: Loading tweak class name cpw.mods.fml.common.launcher.FMLTweaker

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0

at GradleStart.main(GradleStart.java:59)

[00:17:54] [main/ERROR]: Unable to launch

java.lang.ClassNotFoundException: cpw.mods.fml.common.launcher.FMLTweaker

at java.net.URLClassLoader$1.run(Unknown Source) ~[?:1.7.0_67]

at java.net.URLClassLoader$1.run(Unknown Source) ~[?:1.7.0_67]

at java.security.AccessController.doPrivileged(Native Method) ~[?:1.7.0_67]

at java.net.URLClassLoader.findClass(Unknown Source) ~[?:1.7.0_67]

at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.7.0_67]

at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source) ~[?:1.7.0_67]

at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.7.0_67]

at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:104) ~[launchwrapper-1.9.jar:?]

at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.7.0_67]

at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.7.0_67]

at java.lang.Class.forName0(Native Method) ~[?:1.7.0_67]

at java.lang.Class.forName(Unknown Source) ~[?:1.7.0_67]

at net.minecraft.launchwrapper.Launch.launch(Launch.java:97) [launchwrapper-1.9.jar:?]

at net.minecraft.launchwrapper.Launch.main(Launch.java:28) [launchwrapper-1.9.jar:?]

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.7.0_67]

at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.7.0_67]

at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.7.0_67]

at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.7.0_67]

at GradleStart.bounce(GradleStart.java:107) [start/:?]

at GradleStart.startClient(GradleStart.java:100) [start/:?]

at GradleStart.main(GradleStart.java:55) [start/:?]

Thank you for your time.